RE: Official Nitro Evader ST Thread v2.0
As aclark said, sounds like your outdrives and diff gear are in backwards. In other words, the round-slotted thing that are in the diff that the dog bones go into, they are in backwards. You need to take your diff apart and flip the outdrive/diff gear around so they come out the opposite side they are now. The nut and nut holder needs to come out on the engine side of the diff and the head of the screw in the diff that you adjust the tightness of your diff needs to be on the side next to your spur gear.
Hope that helps.